One embodiment of the invention relates to a longitudinal shaft, particularly for use in automobiles having all-wheel drive or rear-wheel drive, comprising a gearbox-side articulation, a differential-side articulation, and a central articulation, each of which have an inner hub and an outer hub that surrounds the former at least in some regions, whereby two shaft segments are connected with one another so as to rotate together, by way of the central articulation. In this connection, the terms “gearbox-side” and “differential-side” are used merely as examples in the sense of this invention, to differentiate the two ends of the longitudinal shaft.
In the case of automobiles, which usually have a motor with a transmission, installed in the front in the direction of travel, the drive torque of the engine is transferred to the rear axle differential for rear-wheel drive, by way of a longitudinal shaft disposed in the direction of travel. In this connection, the longitudinal shaft is subjected to stresses that are as high as ten times the rated torque, as the result of frequently changing torques and speeds of rotation, as well as load shocks. At the same time, the vibrations and noises produced by the longitudinal shaft are supposed to be kept as low as possible.
Usually, a longitudinal shaft of the type stated initially is attached to the transmission output shaft and the differential input shaft, respectively, by way of a flange connection with the outer rings of the gearbox-side articulation and of the differential-side articulation. This flange connection simultaneously serves to center the longitudinal shaft. However, in the case of the high speeds of rotation of the longitudinal shaft that frequently occur during operation, between 8,000 and 10,000 revolutions per minute, even slight balance errors of the longitudinal shaft resulting from insufficient centering will bring about great centripetal forces in the longitudinal shaft, which result in vibrations and disruptive noises.